Apparatus for and method of orienting cords in a molten glass downdraw bowl

ABSTRACT

A directional vane is mounted in a predetermined position within the well or bowl of a molten glass delivery unit to intercept and collect surface cord at such predetermined location within the bowl, and deliver the surface cord in a desired orientation within the molten glass discharged from the delivery orifice. As the molten glass enters the bowl area of the delivery unit, the surface portion thereof which has a tendency to form a surface volatility cord in the delivered glass, flows into contact with opposite sides of the oriented vane and flows downwardly therealong exiting from the discharge orifice at the same angular position as the predetermined setting of the vane.

[451 May 16, 1972 United States Patent Lipp et al.

[541 APPARATUS FOR AND METHOD OF Primary Examiner--Arthur D. KelloggORIENTING CORDS IN A MOLTEN GLASS DOWNDRAW BOWL Attorney-Clarence R.Patty, Jr. and Burton R. Turner ABSTRACT A directional vane is mountedin a predetermined position within the well or bowl of a molten glassdelivery unit to inter- [72] lnventors: George D. Lipp, Corning; VillemRahe, Painted Post; Lawrence B. Roberts, Big Flats, all of NY.

cept and collect surface cord at such predetermined location within thebowl, and deliver the surface cord in a desired [73] Assignee: CorningGlass Works, Corning, NY.

[22] Filed: May 18, 1970 orientation within the molten glass dischargedfrom the delivery orifice. As the molten glass enters the bowl area ofApp]. No.2 the delivery unit, the surface portion thereof which has atendency to form a surface volatility cord in the delivered glass, flowsinto contact with opposite sides of the oriented vane and flowsdownwardly therealong exiting from the discharge orifice at the sameangular position as the predetermined setting of the vane.

6 Claims, 5 Drawing Figures [5 6] References Cited UNITED STATES PATENTS1,675,273 6/1928 Keller.............................,.......65/l29 mslums \\\\\\t.

PATENTEDMAY 16 1912 illllllii t SHEET 1 UF 2 Fig.

2 INVENTORS.

George D. Lipp Vil/em Rahe Lawrence B. Roberts ATTORNEYPATEMTEDMAYISIQTZ 3,663,195

sum 2 BF 2 IN TORS. George L/"pp Vi/lem a e Lowranc- Roberts ATTORNEYAPPARATUS FOR AND METHOD OF ORIENTING CORDS IN A MOLTEN GLASS DOWNDRAWBOWL BACKGROUND OF THE INVENTION The present invention pertains to thedelivery of molten glass, and more particularly to method and apparatusfor coping with surface cord, so that homogeneous glass is delivered todesired forming areas.

The homogeneity of molten glass from a glass delivery unit has alwaysbeen considered important in order to eliminate cord in the resultantproduct and obtain good optical quality. The presence of cord is usuallydue to a variation in glass composition which may be produced by thevolatility of the glass at the surface, with respect to the sub-surfaceglass, thus producing an inhomogeneous glass supply. In the past it hasbeen common practice to employ stirring implements in the bowl andupstream in the forehearth in order to properly homogenize the glassstream and avoid the formation of cord. As an alternative, it has alsobeen known to overflow or skim off the surface glass, by means of anoverflow trough in the bowl area. Usually the overflow trough ispositioned in the nose cord location which is in axial alignment withthe longitudinal glass flow of the delivery unit. Neither the stirringnor the overflow methods of compensating for cord have been entirelysatisfactory. That is, since the stirrer cannot usually be rotatedrapidly enough to function correctly in the bowl, stirring does noteliminate surface volatility cord, but rather has a tendency topartially mix surface contamination with the body glass. Also, a pureskimming operation by an overflow system, on the other hand, increasesthe total glass requirements by the amount which is skimmed off.

SUMMARY or THE INVENTION Whereas the prior art concepts suggestedthorough stirring to avoid cord or the skimming of the cord from thesurface of the glass, the present invention sets forth a novel approachof coping with the cord by directing it toward a specific area in theforming process, wherein it will not be detrimental in the finalarticle. That is, it has been determined that each location within thecross section of the glass delivery feeds a particular portion of anarticle formed therefrom, and accordingly it is an object of the presentinvention to orient the surface cord with a particular location in theglass delivery so as to direct the cord to a desired location in theformed article. For example, the cord may be directed toward an edge ofthe article which is subsequently trimmed, such as in sheet and ribbonglass, or toward a rim area which may be subsequently obscured ortrimmed, such as in a panel or container.

A vane or barrier of any suitable refractory material, such asmolybdenum or platinum-rhodium alloy is positioned within the bowl orwell of the glass feeder with an orientation corresponding to that atwhich it is desired to have the cord exit the discharge opening. Thevane neither rotates nor functions like a stirrer, but rather is a fixedmember which is repositionable with any desired predeterminedorientation in the bowl. Preferably, the vane extends from the centralportion of the bowl outwardly toward the bowl walls, with the upper edgeof the vane projecting above the glass surface and the lower edgeterminating short of the bottom surface. When so positioned within thebowl, the surface volatility cord is intercepted by the vane and flowsdownwardly along opposite sides thereof so as to exit the feeder in apredetermined location within the discharge stream or gob.

It thus has been an object of the present invention to eliminate theneed for how] stirring and costly overflow of nose cord, through theutilization of surface cord glass by directing the same to a positionwithin a formed article which will subsequently be removed or obscured,thus increasing glass utilization.

BRIEF DESCRIPTION OF THE DRAWING FIG. I is a fragmental perspectiveview, partially in section, of a feeder having a directional vane of thepresent invention mounted therein for orienting glass cord.

FIG. 2 is a somewhat schematic plan view of the device shown in FIG. 1illustrating how the surface cord flow paths are intercepted by thedirectional vane.

FIG. 3 is an enlarged sectional plan view of a stream of molten glassdischarged by the device shown in FIG. 1, as viewed along line 3-3thereof.

FIGS. 4 and 5 are somewhat schematic plan views of feeders incorporatingvarious forms of directional vanes embodying the present invention;

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings,and particularly FIGS. 1 and 2, a glass feeder 10, such as a forehearthor the like, is shown having a longitudinal delivery channel 12communicating at its outer end with a bowl 14. The bowl is shown havingcurvilinear sidewalls l6 and a bottom surface 18 provided with adischarge outlet or delivery spout 20. A directional vane or barrier 22is shown mounted upon a shaft 24 extending substantially centrally ofbowl 14 and axially of discharge outlet 20.

Directional vane 22, as shown in FIGS. 1 and 2, is substantially planarand extends radially outwardly from a central portion of bowl 14 toward,but terminating short of, sidewalls 16. The bottom surface ofdirectional vane 22 also terminates in spaced relation with respect tothe bottom surface 18 of the bowl, while the upper surface of vane 22projects above the surface of the molten glass in the bowl, so as toform a barrier and intercept the surface cord in the manner illustratedby the surface cord flow path arrows shown in FIG. 2. Mounting shaft 24is pivotal so as to position directional vane 22 in a desiredorientation within the bowl, such that the surface cord dischargedtherefrom will be delivered to a predetermined location in a subsequentforming operation. That is, the surface volatility cord follows the flowpaths shown in FIG. 2, is intercepted in the bowl area by barrier 22,and flows downwardly along the opposed surfaces of the vane or barrierso as to exit the delivery spout in the same angular position as thebarrier setting.

FIG. 3 illustrates a cross section of molten glass discharged throughdelivery spout 20, with the vaneor barrier oriented in the angularposition shown in FIGS. 1 and 2. That is, the surface cord glass 26 isoriented within the body glass 28 of the discharge, when viewed inhorizontal cross section, in the same angular position as the vanesetting. Since each angular location of the discharge feeds a particularportion of an article to be formed, the vane is oriented so that thecord glass will be directed to a portion of the article to be formedwhich will either be subsequently discarded or obscured in use. In themanufacture of sheet glass, for instance, the cord glass can bedelivered to an edge portion of the sheet, which is normally trimmed offand accordingly its cord quality is of no importance. When a nose cordoverflow was utilized in the manufacture of sheet, both the overflowglass and the edge portion glass were discarded, whereas in the presentinvention the two are combined, providing a resultant gain in glassutilization.

Referring now to FIG. 4, a mounting shaft 30 is shown having adirectional vane or barrier 32 representing a further embodiment of theinvention. Directional vane 32, line vane 22, extends generallyoutwardly from a central portion of the well. However, vane 32 has beenprovided with curvilinear surface portions in order to inhibit anysurface disruption which may occur with a planar vane and thereby permitthe obtainment of a smooth stream-line laminar flow.

Referring now to FIG. 5, a further embodiment of the invention is shownwherein a flow control or stopper member 34 is positioned in the bowl 14to control flow, and a mounting shaft 40 having an angular directionalvane or barrier 42 is positioned slightly off center from the stopper34. However, it should be noted that like planar vane 22, angular vane42 extends outwardly toward the walls of the bowl 14 from asubstantially central portion thereof.

Curvilinear directional vane 32 and angular directional vane 42 bothfunction and operate in the same manner as planar vane 22. That is, thevanes extend above the surface of the molten glass retained in the bowl,and intercept the surface cord causing it to flowdownwardly along theopposed surfaces thereof wherein it is discharged from the delivery unitin the same stream location as the angular position of the vane.Although all embodiments of the directional vanes are shown in the sameorientation within the bowl, it should be understood that shafts 24, 30and 40 are pivotal so as to fixidly re-position the vanes in virtuallyany orientation within the bowl proper. In addition, the various vanesmay be interchanged among the various shafts so that vane 42 may bepositioned concentric with the discharge orifice 20, whereas vanes 22and 32 may be in a slightly ofi-set position such as shown in FIG. 5. Inview of the fact that the vanes may be positioned on the center line orslightly off center, the invention is equally applicable to both gobfeeders and stream feeders.

Although the now preferred embodiments of the invention have beendisclosed, it will be apparent to those skilled in the art that variouschanges and modifications may be made thereto without departing from thespirit and scope thereof as defined in the appended claims.

We claim:

1. A method of delivering molten glass wherein molten glass is suppliedto a glass delivery bowl and discharged downwardly below the surface ofsuch supply through a delivery outlet, the improvement comprising thesteps of intercepting surface cord on the molten glass in the bowl at apredetermined location, directing such cord downwardly through themolten glass within the bowl at such predetermined location, anddischarging molten glass from the bowl with the surface cord in the samerelative location in the glass discharge as the predetermined locationin the bowl at which such cord was intercepted.

2. A method of delivering molten glass as defined in claim 1 includingthe steps of providing a barrier within the bowl area which projectsabove the surface of the glass retained therein for intercepting thesurface cord, flowing such surface cord downwardly along wall portionsof such barrier, and discharging molten glass from the feeder with thesurface cord in the same orientation within the discharge as theorientation of the barrier in the bowl.

3. A method of delivering molten glass as defined in claim 2 includingthe step of intermittently discharging molten glass in the form of gobs.

4. A method of delivering molten glass as defined in claim 2 includingthe step of continuously delivering a stream of molten glass from thedischarge outlet with the cord glass being located in a predeterminedorientation relative to a horizontal cross-section of such stream.

5. A method of delivering molten glass as defined in claim 2 includingthe step of re-positioning the barrier within the bowl to obtain thedischarge of the cord glass with a different predetermined orientationwithin the discharged glass.

6. Glass delivery apparatus including a substantially horizontaldelivery channel communicating at one end with a source of molten glassand at its opposite end with a stationary bowl portion, said bowlportion having a bottom surface at substantially the same level as thebottom surface of said delivery channel, a downwardly open dischargeoutlet formed in the bottom surface of said bowl portion, staticintercepting and directing means positioned within said bowl portionabove said discharge outlet for intercepting surface cord on flowingglass supplied to said stationary bowl portion by said source of moltenglass and for directing such surface cord downwardly so as to bedischarged with a predetermined orientation within the flow deliveredfrom the discharge outlet, said static intercepting and directing meansincluding a fixed vane member, said vane member extending from a centralposition within said bowl substantially in axial alignment with saiddischarge outlet radially outwardly toward side wall portions of thebowl, said vane member having an upper edge pro'ecting above the moltenglass within said bowl and a lower e ge terminating short of a bottomsurface of such bowl, and means for positionably supporting said vane ina desired orientation with said bowl.

1. A method of delivering molten glass wherein molten glass is suppliedto a glass delivery bowl and discharged downwardly below the surface ofsuch supply through a delivery outlet, the improvement comprising thesteps of intercepting surface cord on the molten glass in the bowl at apredetermined location, directing such cord downwardly through themolten glass within the bowl at such predetermined location, anddischarging molten glass from the bowl with the surface cord in the samerelative location in the glass discharge as the predetermined locationin the bowl at which such cord was intercepted.
 2. A method ofdelivering molten glass as defined in claim 1 including the steps ofproviding a barrier within the bowl area which projects above thesurface of the glass retained therein for intercepting the surface cord,flowing such surface cord downwardly along wall portions of suchbarrier, and discharging molten glass from the feeder with the surfacecord in the same orientation within the discharge as the orientation ofthe barrier in the bowl.
 3. A method of delivering molten glass asdefined in claim 2 including the step of intermittently dischargingmolten glass in the form of gobs.
 4. A method of delivering molten glassas defined in claim 2 including the step of continuously delivering astream of molten glass from the discharge outlet with the cord glassbeing located in a predetermined orientation relative to a horizontalcross-section of such stream.
 5. A method of delivering molten glass asdefined in claim 2 including the step of re-positioning the barrierwithin the bowl to obtain the discharge of the cord glass with adifferent predetermined orientation within the discharged glass. 6.Glass delivery apparatus including a substantially horizontal deliverychannel communicating at one end with a source of molten glass and atits opposite end with a stationary bowl portion, said bowl portionhaving a bottom surface at substantially the same level as the bottomsurface of said delivery channel, a downwardly open discharge outletformed in the bottom surface of said bowl portion, static interceptingand directing means positioned within said bowl portion above saiddischarge outlet for intercepting surface cord on flowing glass suppliedto said stationary bowl portion by said source of molten glass and fordirecting such surface cord downwardly so as to be discharged with apredetermined orientation within the flow delivered from the dischargeoutlet, said static intercepting and directing means including a fixedvane member, said vane member extending from a central position withinsaid bowl substantially in axial alignment with said discharge outletradially outwardly toward side wall portions of the bowl, said vanemember having an upper edge projecting above the molten glass withinsaid bowl and a lower edge terminating short of a bottom surface of suchbowl, and means for positionably supporting said vane in a desiredorientation with said bowl.